Kunzea robusta de Lange & Toelken

(Figs 53, 54, 55, 56, 57, 58). Growth habit trees (8–)20–25(–30) m tall, rarely decumbent shrubs up to 1 × 3 m; trees, depending on local conditions, mostly forming broad spreading canopies; in exposed situations branching at or close to the trunk base, while those growing in dense stands or sheltered sites usually with the lower 50–75% of the trunk devoid of branches. Trunk 1(–6) erect, 0.10–0.65(–1.0) m d.b.h.; mature trees usually devoid of branches for at least the first 1–3 m, basal portion of trunks covered with firm to semi-detached, stringy to coarsely tessellated, corky-coriaceous bark. Bark early bark subcoriaceous, grey-brown, cinnamon brown or dark brown, elongate, usually bearing deep transverse cracks (especially on branch flanges and decurrent leaf bases) otherwise firmly attached, margins elongate, sinuous, ± entire with scarcely any flaking; old bark either stringy, or coarsely tessellated, mostly corky-coriaceous, though in dense forest stands tending toward subcoriaceous or chartaceous, firmly attached above, detaching basally, often hanging semidetached; peeling upwards along trunk in narrow to broad, tabular strips up to 4 m long, margins ± entire to weakly irregular, usually straight; upper surface either ± smooth with coarsely tessellated but firm upper surface, or deeply and longitudinally corrugated and cracked (rarely peeling); early bark flakes usually crumbling in hand, old bark strips firm and not crumbling, snapping with a ± entire margin. Branches initially arising from or close to trunk base; these initial branches progressively dying, such that branches are increasingly confined to the upper 50–75% of trunk. Branches weakly flexuose or not, initially erect, soon arching outwards and spreading with distal ends mostly erect, rarely with whole branch or distal portion completely pendulous; branchlets numerous, slender, clustered toward branch ends, ± quadrangular to subterete, with leaves ± evenly spaced along length or in exposed situations, crowded toward apices; branchlets sericeous, indumentum copious, hairs hyaline to translucent (appearing white when young, maturing grey); mostly either long or short antrorse-appressed; if long, then usually weakly flexuose hairs 0.15–0.20(–0.38) mm long; if short, not flexuose, 0.09–0.15 mm long. In eastern Coromandel Peninsula and coastal East Cape to near Mahia Peninsula, branchlet indumentum in mixtures of mainly short (0.03–)0.05(–0.08) mm long divergent hairs, and sparse, 0.1–0.2 mm long, antrorse-appressed hairs (see Fig. 57A–D). In the Rangitikei region, seedling and juvenile plants up to 2 m tall have branchlet hairs mostly divergent, short (0.04–)0.08(–0.10) μm long. Vegetative buds conspicuous; at resting stage 0.3–2.8 mm diam., ovoid to broadly ellipsoid; scales scarious, deciduous or persistent, 0.6–0.8(–1.4) mm long, amber, red-brown to wine-red, basally broadly ovate, grading through ovate-deltoid to broadly lanceolate, cuspidate; midrib prominent, strongly keeled, prolonged to short cuspidate tip, lateral veins absent, colliculate, with oil glands, scattered, colourless, drying the same colour as the scale body, apical scale margins, keel, and keel apex copiously covered in long, white, sericeous hairs. Leaves with distinct juvenile and adult forms, sessile to shortly petiolate, well spaced to crowded along branchlets, spreading, suberect to patent, flat to weakly recurved in apical 30–50%, light green or dark green above, paler beneath; oblanceolate, broadly oblanceolate, broadly lanceolate, lanceolate to linear-lanceolate, rarely elliptic to obovate; apex subacute to acute, rarely obtuse, rostrate or shortly apiculate, base attenuate to narrowly attenuate; adaxial surface flat, weakly convex to slightly v-shaped; oil glands up to 600, evident when fresh, becoming more conspicuous when dry, midrib very slightly raised near base, otherwise not evident for rest of length, leaf base finely covered in antrorse-appressed, silky hairs, glabrate; abaxial surface slightly concave to flat or v-shaped in apical recurved portion otherwise weakly concave, finely glandular punctate, oil glands abundant up to 500, more evident when dry; midrib slightly raised for entire length, prolonged slightly at apex, hairs as for adaxial surface; lamina margin initially finely covered with a thin often interrupted band of 0.2–0.8 mm long, flexuose, spreading to antrorse-appressed hairs not or rarely meeting at apex; hairs mostly shedding with age, usually with only the basal portion ± retained. Lamina of juvenile plants from mainly coastal areas and northern North Island (14.6–)19.0(–28.4) × (1.6–)2.2(–2.5) mm; from inland areas, especially the Rangitikei, central and northern Wairarapa and Mt Egmont, (3.2–)4.6(–6.3) × (0.7–)1.2(–1.5) mm; adult lamina of plants from mainly coastal areas and northern North Island (4.9–)14.2(–20.1) × (0.9–)1.7(–3.0) mm; from inland areas, especially from the central North Island, Rangitikei, Wairarapa, and Central Otago (5.8–)9.3(–12.3) × (1.2–)1.8(–2.2). Perules usually very conspicuous, rarely obscured by surrounding leaves; at resting stage 1.9–3.0 mm diam., broad ovoid, ovoid, narrow-ovoid to broadly ellipsoid, squamiform; scales scarious, persistent, 0.6–1.0(–1.6) mm long, red-brown to red, basally broadly ovate, grading through ovate-deltoid to broadly lanceolate, cuspidate; midrib prominent, becoming even more on old or dried specimens, strongly keeled, prolonged to a short cuspidate tip (this becoming more obvious on drying), lateral veins absent, colliculate, with oil glands, scattered, colourless, drying the same colour as the scale body, upper scale margins, keel, and keel apex copiously covered in long, white, silky hairs. Inflorescence mostly a compact corymbiform to shortly elongate (1–)12(–30)-flowered botryum up to 60 mm long; usually on brachyblasts with the terminal shoot corymbiform or extending toward the end of the flowering season as a slightly longer (up to 80 mm long) 4–12-flowered, elongate botryum; flowers usually crowded, terminal portion usually bearing undeveloped flowers and dormant vegetative bud or active vegetative growth. Inflorescence axis densely invested with short, spreading to antrorse-appressed silky hairs. Pherophylls deciduous or more or less persistent; squamiform grading into foliose; squamiform pherophylls tightly clasping pedicels, 0.4–1.2 × 0.3–0.6 mm, red-brown to brown, broadly to narrowly deltoid or lanceolate, apex acute, subacute to obtuse, weakly keeled, upper keel and margins finely ciliate; foliose pherophylls spreading, flat or weakly recurved, (6.0–)9.0(–17.9) × (1.1–)1.2(–1.8) mm, green, elliptic, oblanceolate, broadly lanceolate to lanceolate, apex obtuse, cuspidate, base attenuate; adaxial surface usually convex to weakly v-shaped, oil glands 10–30(–50), midrib slightly raised near base, evident for rest of length, basally covered in sparse to dense, antrorse-appressed, silky hairs; abaxial surface flat or weakly convex, glandular punctate, oil glands 20–40; midrib raised for most of length, densely covered in antrorse-appressed, silky hairs to apex, lamina margin obscured by dense covering of antrorse-appressed hairs. Pedicels (1.2–)3.8(–5.2) mm long at anthesis, usually elongating slightly after anthesis, terete, sparsely to densely invested in antrorse-appressed, weakly flexuose, silky hairs. Flower buds pyriform to obconic, apex flat or weakly domed prior to bud burst; calyx valves not meeting. Fresh flowers when fully expanded (4.3–)7.7(–12.0) mm diam., usually reducing in size toward end of flowering season. Hypanthium (2.1–)3.1(–4.1) × (3.0–)3.9(–5.2) mm, with free portion 0.4–0.9 mm long, dark green or red-green, drying green-brown or red-brown; mostly broadly obconic to turbinate, sometimes cupular, terminating in dark-green to red-green coriaceous rim bearing five persistent calyx lobes. Hypanthium surface when fresh faintly ribbed and sparingly dotted with pink or colourless oil glands, these drying dull yellow-brown or brown; either finely pubescent with the ribs and veins conspicuously covered in longer silky, antrorse-appressed hairs, or glabrous; hypanthium similar when dry though with the ribs more strongly defined and clearly leading up to calyx lobes. Calyx lobes 5, persistent, mostly spreading, coriaceous, (0.52–)0.83(–1.1) × (0.60–)0.90(–1.4) mm, pale green to red-green, broadly ovate, ovate-truncate to broadly obtuse, weakly keeled, external face of keel usually obscured by a broad band of antrorse-appressed, silky, white hairs, otherwise glabrous; margins white or pale green often flushed pink, surface somewhat sparsely glandular punctate, oil glands ± colourless when fresh drying dark yellow to yellow-brown, otherwise glabrate. Receptacle green or pink at anthesis, consistently darkening to crimson after fertilisation. Petals 5(–6), (1.5–)2.6(–3.8) × (1.3–)2.6(–3.6) mm, white, rarely pink (sometimes drying pale yellow or cream), spreading, orbicular, suborbicular to ovate, apex rounded to obtuse, margins ± finely and irregularly denticulate or crimped 1–6 or more times, rarely entire, oil glands colourless, drying opaque or grey. Stamens (15–)33(–58) in 2 weakly defined whorls, arising from receptacular rim, filaments white. Antipetalous stamens 3–5(–6) sometimes petaloid, antisepalous stamens (3–)5(–8). Outermost antipetalous stamens usually outcurved, sometimes weakly incurved or in mixtures of both on filaments 1.5–4.6(–5) mm long, inner stamens usually at the base of the outermost antipetalous pair (0.8–)2.3–3.1 mm, weakly incurved. Antisepalous stamens mostly shorter than outermost antipetalous stamens, sometimes of comparable length, generally 0.6–1.2 mm, weakly to strongly incurved, very rarely a few outcurved. Anthers dorsifixed, 0.38–0.63 × 0.18–0.32 mm, ellipsoid to ovoid-ellipsoid or deltoid, latrorse. Pollen white (9.1–)14.7(–15.1) μm. Anther connective gland prominent, light pink, salmon pink, yellow to orange when fresh, drying dark orange, orange-brown or dark brown, spheroidal, finely rugulose or papillate. Ovary 5(–6) locular, each with 15–26(–36) ovules in two rows on each placental lobe. Style 2.0–2.5(–3.5) mm long at anthesis, elongating slightly after anthesis, white or pinkish-white; stigma broadly capitate, at least 1.5× style diam., flat, greenish-white or pale pink, flushing red after anthesis, surface finely granular-papillate. Fruits mostly all falling within 1–2 months of seed dehiscence, but a few long persistent, (2.2–)3.8(–4.6) × (3.2–)4.0(–5.3) mm, initially dark green to chesnut-brown fading with age to greyish white, obconic, broadly obconic to ± turbinate, rarely cupular; veins and ribs ± conspicuous on drying; external surface distinctly hairy, very rarely glabrescent or glabrous; hairs short to long antrorse-appressed; calyx valves incurved, splits concealed by dried, erect, free portion of hypanthium. Seeds 0.9–1.0(–1.1) × 0.35–0.40(–0.48) mm, oblong, oblong-obovate, oblong-elliptic, curved near apex, laterally compressed, 2–3-angled with convex to flattened faces, apex rounded to subacute, base oblique, ± flattened; testa semi-glossy, orange-brown to dark brown, surface coarsely reticulate. FL: (Aug–)Nov–Jan–Feb(–Jun). FT: (Jul–)Feb–Apr(–May). Chromosome Number n = 11II, 2n = 22, 23 (see de Lange and Murray 2004).

(Fig. 59). Endemic. New Zealand, North and South Islands (sea level – 1000 m a.s.l.). In the North Island widespread with the exception of Te Paki and the sand tombolo of Te Aupouri. Scarce in Taranaki, from where de Lange (2006) (treated there as Kunzea aff. ericoides (B)) had erroneously stated that the species was absent from Mt Taranaki/Egmont because at that time the populations of Kunzea on that mountain were believed to represent another allied, but potentially distinct, species, Kunzea aff. ericoides (f) (see de Lange and Murray 2004; de Lange et al. 2005). In the southern one-third of the North Island, it appears to be absent from Kapiti Island from where only Kunzea amathicola has thus far been collected. In the South Island, Kunzea robusta, although wide ranging, is often absent over large parts of seemingly suitable habit. It is also naturally absent from most of north and south-west Nelson where it is replaced by Kunzea ericoides and, in the extreme north-west, Kunzea amathicola. However, occasional trees and stands grow near Wangapeka and in places along the Buller River. It was also planted around Totaranui, Abel Tasman National Park from where it began to naturalise.Those plantings have now been eradicated. On the West Coast, in an area centred on Fairdown, Westport, and Cape Foulwind and also within the lower Grey River catchment, Kunzea robusta is locally abundant. It also grows to the west of the main divide along the upper Ahaura River, below Mt Ranunculus, and on the foothills of the Alexandra Range. South of here, Kunzea robusta is scarce with only isolated, mainly roadside stands present near Kumara and Hokitika. The close association of these stands to roadsides suggests that the stands may not be natural, or that the species has benefited from the frequent disturbance caused by road construction and ongoing maintenance. Occasional trees of this species have also been collected from Okarito (e.g., B. H. Macmillian 97/22 & E. H. Woods (CHR 512939)) where they occur as planted specimens and from which source it is now naturalising. In the eastern South Island this species is more widespread, though initially strictly as a coastal and lowland tree of the Marlborough Sounds south to about North Canterbury. In North Canterbury, Kunzea robusta occasionally extends well inland up the river valleys where it is sympatric with and eventually replaced by Kunzea serotina. South of there, on Banks Peninsula, Kunzea robusta seems to be the only species present, while on the adjacent Canterbury Plains it is completely replaced by Kunzea serotina until, on the slightly more elevated foothills of south Canterbury, Kunzea robusta reappears as a local dominant. In north-eastern Otago, Kunzea robusta is common around Trotters Gorge and the Horse Range but south of here it has an otherwise mainly coastal distribution, reaching its greatest abundance around Dunedin and on the adjacent Otago Peninsula. A few inland locations are known, especially around Lakes Hawea and Wanaka, where the species is sympatric with Kunzea serotina. Kunzea robusta is also common along the northern and eastern foothills of the Dunstan Range south of which it occurs only very locally, in isolated patches along the Clutha River as far south as Kaitangata and Balclutha. These southerly outliers are not only the southern limit for the species but also for the genus worldwide.